It is known that a compound of the formula:
(hereinafter, the compound will be referred to as “Compound A”) is an endothelin receptor antagonist, and is useful for treating various circulatory system diseases such as hypertension, ischemic disorders, cerebral circulatory disorders, renal disorders, circulatory insufficiency of various organs, asthma, stroke, cerebral infarction, cerebral edema and the like (see Patent Literatures 1 and 2).
Further, a free compound of Compound A of the formula (I):
(hereinafter, the compound will be referred to as “Compound (I)”) has been already isolated as pale yellow needle crystals by using ethyl acetate as a solvent for recrystallization (see Non-patent Literature 1).
Patent Literature 3 discloses a pharmaceutical preparation obtained by freeze-drying a solution or suspension prepared by adding a basic substance to Compound A or Compound (I).
Patent Literature 4 discloses a process for isolating Compound (I) as crystals from a solution prepared by adding an organic solvent and water to a reaction mixture containing Compound (I). However, in Patent Literature 4, only ethyl acetate is mentioned as a specific example of the organic solvent, and there is no reference made to a form II crystal of Compound (I) of the present invention.    [Non-Patent Literature 1] Organic Process Research & Development, 1999, vol. 3, pp.347-351    [Patent Literature 1] Japanese Patent Laid-open No. H7-53484    [Patent Literature 2] Japanese Patent Laid-open No. H7-316188    [Patent Literature 3] WO 03/007967    [Patent Literature 4] WO 03/080643